Comparison Of Pentacam And Anterior Segment Optical Coherence Tomography In Measuring Ophthalmic Anterior Segment Biological Parameters

Objective: The Pentacam anterior segment analyzer and the anterior segment optical coherence tomography(AS-OCT)are clinically used anterior segment measurements.Due to different working principles,the data obtained are also different.This study compared the differences in corneal curvature and corneal astigmatism,central corneal thickness,and anterior chamber depth measured by Pentacam and AS-OCT in young myopic preoperative and senile cataract patients,respectively.Provide a reference for clinical use.Methods:Prospective clinical study.From September 2017 to November 2017,Totally64 preoperative examinations(124 eyes)and 61 senile cataract patients(85 eyes)were selected.Pentacam and AS-OCT were used to measure the people's parameters of the ophthalmic anterior segment.The paired sample t-test was used to compare the differences between the two instruments in the two groups.The correlation of the data was analyzed by Pearson correlation analysis,and the consistency of the results was analyzed by Bland-Altman.Results : In myopia group,steep Keratometry(Ks),flat Keratometry(Kf),mean Keratometry(Km),astigmatism parameter J0,central corneal thickness(CCT),anterior chamber depth(ACD)measured by the two instruments were different(P < 0.05),and astigmatism parameters were measured.There was no significant difference between the two instruments about astigmatism parameter J45(P > 0.05).In cataract group,there was no significant difference in Ks,Kf,Km and J45 measured by the two instruments (P > 0.05),but the astigmatism parameters J0,CCT and ACD measured by the two instruments showed differences(P < 0.05).The results of Ks,Kf,Km,J0,J45,CCT and ACD measured by two instruments were linearly correlated in both groups(P < 0.001).The 95% limits of agreement(Lo A)of Ks,Kf,Km,J0,J45,CCT and ACD measured in myopic group were small,and the absolute values of upper and lower limits were 0.61 D,0.67 D,0.50 D,0.36 D,0.39 D,15.5um and 0.24 mm,respectively.The maximum absolute values of 95% limits of agreements of Ks,Kf,Km,J0,J45,CCT and ACD in cataract group were 0.85 D,0.82 D,0.71 D,0.60 D,0.47 D,27.3?m and 0.34 mm,respectively.The consistency intervals of Ks,Kf and Km were larger and the consistency was worse.Conclusion: 1.Comparing the consistency of the two groups,we found that 95% limits of agreement in cataract group was significantly wider than that in myopia group,which suggested that age-related factors such as shorter tear film rupture time and opacity of refractive interstitium would affect the repeatability and consistency of the results;2.When measuring corneal curvature and astigmatism,the two instruments in young patients group have good consistency and can be used interchangeably.As AS-OCT measurement time is short and the measurement process is non-irritating,AS-OCT is preferred.In elderly patients group,the consistency of the two instruments is poor.It is preferred to use Pentacam,because Pentacam is more accurate in measuring corneal curvature and astigmatism parameters than the anterior segment OCT in measuring principle;3.When measuring the central corneal thickness and anterior chamber depth,the two groups of people have good consistency and can be used interchangeably.In clinical application,Pentacam and AS-OCT combined use can better serve refractive surgery.